For purposes of this disclosure, “bulk material” as used herein will refer to substantially loose materials such as, but not limited to, soils and soil components such as silt, sand, clay, gravel, and coal and ores as transported within or from mining and processing operations. Examples further include loose aggregate materials and other multicomponent materials including those with liquid components and/or those that exhibit flow characteristics such as asphalt and unset concrete mixes. Such materials have a tendency to stick and clump to a bed of a dump truck or other dumping vehicle so that only part of a load is dumped when the bed is fully elevated to a dumping position.
“Dump body” as used herein refers to a container for temporary storage and possibly transport of a load of bulk material in which the container is tilted in order to gravitationally discharge its load. Tilting is by rotation of the dump body about an approximately horizontal axis affixed to a base, which may be the ground, or a frame resting on or attached to ground for stationary storage facilities or, for transport vehicles, a base may be a frame of a truck as with a dump truck or a frame of an ore car of a mining operations train. A dump body has a bed which, as used herein, is a lower surface including a floor of the dump body and from which bulk material is gravitationally discharged by dump body inclination, hereafter referred to as dumping.
A common problem with dumping certain bulk materials, such as with moist, compactible, and/or otherwise sticky bulk materials, with conventional dump bodies is that effective volumetric capacity of the dump body is substantially diminished because appreciable bulk material may tend to clump or adhere to the bed of the dump body after a dumping operation. In these situations, residual material clinging to a bed of a truck may be substantial after just one or a few loads, thus significantly reducing efficiency of transport and dumping operations. With these conventional dump body systems, residual material must be removed manually, but this consumes valuable equipment operations time and requires considerable physical exertion. In other instances, a truck drive may be engaged while the dump body is elevated to the dump position, and the vehicle “jogged” in an effort to dislodge residual material clumped to sides and floor of the dump body. Such a practice is obviously to the detriment of the dump body and transport vehicle.
Applicants' previous patent (U.S. Pat. No. 5,002,340) which is incorporated herein in its entirety by reference, discloses a dump truck bed scraper that is selectively actuated to substantially remove residual adhering bulk material while a truck's dump body is inclined for dumping. This bed scraper apparatus includes a bed scraper carriage that is pulled along a dump body's bed floor via cables driven by an electric winch. The scraper carriage is provided with rigidly attached scraping blades that contact and dislodge adhering bulk material from the floor of the bed. While applicant's prior truck bed scraping apparatus successfully removes residual material during dumping operations, such apparatus is expensive to fabricate and install, occupies considerable space in and around a dump body, is complex mechanically and is therefore maintenance intensive. In addition, the systems operating the scraper are separate from the dump body systems, and must be separately actuated.
Considering the deficiencies described in the aforementioned dump truck bed-cleaning system, it is an object of this invention to provide an inexpensive, reliable and mechanically robust dump body bed cleaning or clearing system that is actuated by a dumping operation of the dump body, and requires no additional activation by an operator. Other objects of the invention will become apparent upon a reading of the following disclosure.